This invention relates to a cutting machine particularly suitable for dicing a semiconductor wafer. More specifically, the invention relates to a cutting machine of the type having two cutting means whose rotating shafts are arranged on a straight line and whose rotating blades are mounted on the inner ends of the rotating shafts and are opposed to each other.
Japanese Unexamined Patent Publication No. 2001-7058 discloses a cutting machine including two cutting means and particularly suitable for dicing a semiconductor wafer with a high efficiency. Such a cutting machine has a housing slenderly extending in a fore-and-aft direction, and an operating panel is disposed on a front surface of the housing. On one side of the housing, a cassette-placing zone, a chucking zone, and a cleaning zone are arranged sequentially in a rearward direction. A cutting zone is disposed at the center in the fore-and-aft direction on the other side of the housing. Cassette supporting means is disposed in the cassette placing zone, and cleaning means is disposed in the cleaning zone. Two cutting means, i.e., first cutting means and second cutting means, are disposed on the other side of the housing. The first cutting means has a first rotating shaft and a cutting blade mounted on the first rotating shaft. The second cutting means has a second rotating shaft and a cutting blade mounted on the second rotating shaft. The first rotating shaft and the second rotating shaft extend on a straight line in the fore-and-aft direction on the other side of the housing. The first cutting blade and the second cutting blade are mounted on the inner end, i.e., the rear end, of the first rotating shaft, and the inner end, i.e., the front end, of the second rotating shaft, respectively, and located opposite each other.
A cassette accommodating a plurality of workpieces, optionally a plurality of semiconductor wafers, is placed on the cassette supporting means, and the workpieces accommodated in the cassette are sequentially delivered to the chucking zone. The delivered workpiece is chucked onto the chuck means, and conveyed to the cutting zone together with the chuck means. In the cutting zone, the workpiece is cut by the first cutting blade and the second cutting blade. Then, the workpiece is returned to the chucking zone together with the chuck means, and transported from the chucking zone to the cleaning zone. In the cleaning zone, the workpiece is cleaned, then transported to the chucking zone, and then brought into the cassette.
The above-described cutting machine disclosed in Japanese Unexamined Patent Publication No. 2001-7058 is made compact, by skillful arrangement of the various zones, in comparison with other types of cutting machines including two cutting means, for example, the cutting machines disclosed in Japanese Unexamined Patent Publication Nos. 1999-26402 and 1999-74228. However, this cutting machine is still unsatisfactory, and poses the following problems: The cutting blades in the two cutting means wear upon execution of cutting, and need replacement. However, there is considerable distance from the front of the housing to the position of mounting of the cutting blade. Thus, it is very difficult, if not impossible, to perform an operation for replacing the cutting blade from the front of the housing. Usually, an operator has to be situated on the side of the housing in order to carry out the operation for replacing the cutting blade. This makes the replacement operation relatively complicated. To enable the operator to be situated on the side of the housing during replacement of the cutting blade, there is need to secure a required space near the side of the housing. Thus, a relatively large space is required for installing the cutting machine. In using the cutting machine for cutting a semiconductor wafer, it is necessary to install the cutting machine in a so-called clean room. In this sense, the necessity for the relatively large space for installation of the cutting machine is not a negligible problem.
A principal object of the present invention is to improve the layout of various zones in a cutting machine of the type having two cutting means, facilitate an operation for replacement of a cutting blade, and reduce a space necessary for installation of the cutting machine.
The inventors of the present invention conducted in-depth studies, and have found that the above object can be attained by arranging a chucking zone in a widthwise center, a cassette placing zone on one side of the chucking zone, and a cleaning zone on the other side of the chucking zone in a front half of a housing, arranging a cutting zone in a widthwise center in a rear half of the housing, and designing rotating shafts of two cutting means to extend straightly widthwise in the rear half of the housing.
According the present invention, there is provided a cutting machine comprising:
a housing having an operating panel disposed on a front surface thereof; and wherein
a chucking zone located in a widthwise center, a cassette placing zone located on one side of the chucking zone, and a cleaning zone located on an opposite side of the chucking zone are arranged in a front half of the housing, while a cutting zone located in the widthwise center is arranged in a rear half of the housing;
cassette supporting means is disposed in the cassette placing zone, and cleaning means is disposed in the cleaning zone;
chuck means is disposed so as to be movable in a fore-and-aft direction between the chucking zone and the cutting zone;
first cutting means and second cutting means are disposed in the rear half of the housing, the first cutting means has a first rotating shaft and a first cutting blade mounted on the first rotating shaft, the second cutting means has a second rotating shaft and a second cutting blade mounted on the second rotating shaft, the first rotating shaft and the second rotating shaft extend straightly in a width direction in the rear half of the housing, and the first cutting blade and the second cutting blade are mounted on a widthwise inner end of the first rotating shaft and a widthwise inner end of the second rotating shaft, respectively, and located opposite each other; and
a cassette accommodating a plurality of workpieces is placed on the cassette supporting means, the workpieces accommodated in the cassette are sequentially delivered to the chucking zone, the delivered workpiece is chucked onto the chuck means in the chucking zone, and conveyed to the cutting zone together with the chuck means, and the workpiece on the chuck means is cut by the first cutting blade and the second cutting blade in the cutting zone, then returned to the chucking zone together with the chuck means, transported from the chucking zone to the cleaning zone, cleaned in the cleaning zone, then transported to the chucking zone, and brought into the cassette.
Preferably, temporary support means is disposed in the chucking zone, and the workpiece delivered from the cassette to the chucking zone is first placed on the temporary support means, then transported from a site on the temporary support means to a site on the chuck means, cut, cleaned, and transported from the cleaning zone to the chucking zone, whereafter the workpiece is placed onto the temporary support means, and brought into the cassette. Preferably, the temporary support means is composed of a pair of support members, and the pair of support members are free to move between an operating position, where the support members are located at a predetermined spacing relative to each other and the workpiece is placed across the support members, and a non-operating position where the support members are moved from the operating position away from each other to allow the workpiece to descend through a gap therebetween, and when the chuck means is located in the chucking zone, the chuck means is positioned below the temporary support means. In preferred embodiments, the workpiece is a semiconductor wafer, and the first cutting blade and the second cutting blade are shaped as disks containing diamond grains and dice the semiconductor wafer.